RU2456303C1 - Method of producing polymers containing dichlorocyclopropane groups - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves reaction of atactic 1,2-polybutadiene with chloroform in aqueous solution of an alkali metal in the presence of a quaternary ammonium salt as a phase-transfer catalyst at temperature 40-50°C for 2-6 hours, characterised by that synthesis is carried out in molar ratio 1,2-polybutadiene:CHCl₃:NaOH:catalyst equal to 1:4-14:1.5-2:0.001-0.002. The starting polymer used is atactic 1,2-polybutadiene with number-average molecular weight Mn from 20000 to 70000, content of 1,2- and 1,4-polymerisation links in macromolecules

of 60-75 and 25-40 mol %, respectively.

EFFECT: obtaining polymer products with high degree of functionalisation.

2 cl, 1 tbl, 7 ex

Description

The invention relates to the field of macromolecular compounds, in particular to the production of polymer products containing dichlorocyclopropane groups in the composition of macromolecules, of the general formula (I):

These polymer products are copolymers containing dichlorocyclopropane groups in the side chains (b) and in the main chain (d) of the macromolecules, as well as carbon-carbon double bonds in the side chains (a) and in the main chain (c). Polymer products (1) can find application in the composition of adhesive compositions, sealants, paints and varnishes, as modifiers and flame retardants in various compositions of thermoplastics and elastomers.

Known methods for producing polymer products (1) by chemical modification of polybutadiene containing 1,2- and 1,4-polymerization of 1,3-butadiene in the composition of the macromolecules. Polybutadiene, which is the feedstock for producing polymers (1), is synthesized by polymerization of 1,3-butadiene on complex catalysts [RF Patent 2177008, cl. C08F 136/06, C08F 36/06, C08F 36/04, C08F 4/70; publ. 12/20/2001. U.S. Patent 4,182,813, CL C08F 136/06, C08F 36/00, C08F 4/00; publ. 01/08/1980. RF patent 2139299, cl. C08F 136/06; publ. 10/10/1999].

The method for producing polymers of formula (1) is based on the generation of dichlorocarbene by the action of an aqueous solution of sodium hydroxide on chloroform in the presence of an interphase transfer catalyst (equation 2) and its subsequent attachment in situ to the double bond of polybutadiene with the formation of a polymer product containing dichlorocyclopropane groups in the side units and in the main chain of macromolecules (equation 3):

The known method [RF patent 2073019, class. C08F 8/18; C08F 19/18; publ. 02/10/1997] the preparation of polymers containing dichlorocyclopropane groups, consisting in the interaction of cis-1,4-polybutadiene with chloroform and an aqueous solution of an alkali metal in the presence of a phase transfer catalyst, which is used as a quaternary ammonium salt or tertiary amine. The reaction is carried out in a hydrocarbon solvent (toluene, gasoline, cyclohexane or a mixture thereof) at a temperature of 20-40 ° C for 0.5-4 hours at a molar ratio of polybutadiene: CHCl ₃ : NaOH: catalyst equal to 1: 1-3: 0 3-2: 0.002-0.2. The resulting polymer product is washed with water, and then isolated by water degassing. The degree of functionalization (content of dichlorocyclopropane groups) of the polymer is from 10 to 80 mol.%.

However, this method does not allow to obtain polymers of the formula (1) with a total content of lateral units (a + b) of more than 10 mol.%.

Closest to the proposed invention is a method (A. Konietzny, U.Biethat "Zur Anlagerung von Dichlorcarben an niedermolekulare cis- und Vinyl-cis-Polybutadiene" // Die Angewandte Makromolekulare Chemie, 1978, Vol. 74, P.61-79, Nr. 1176) for the preparation of polymers containing dichlorocyclopropane groups, based on the interaction of 1,2-polybutadiene (1,2-PB) with chloroform and an aqueous alkali metal solution in the presence of an interphase transfer catalyst, which is used as a quaternary ammonium salt or tertiary amine. In this method, to obtain modified polymer products using low molecular weight 1,2-polybutadiene atactic structure with a number average molecular weight Mn from 790 to 1800 amu and a content of 1,2 units of not more than 52%. The reaction is carried out at a temperature of 40-50 ° C for 2-6 hours at a molar ratio of 1,2-polybutadiene: CHCl ₃ : NaOH: catalyst equal to 1: 2-3: 0.5-2: 0.001-0.005. The degree of functionalization of the polymer is from 20 to 92 mol.%.

However, this method has several serious limitations:

- this method cannot be obtained polymers of the formula (1) with a total content of lateral units (a + b) of more than 52%, the properties of which differ significantly from the properties of the polymers described in the prototype;

- the method does not allow to obtain modified polymer products with a molecular mass of M _n more than 2000, and the resulting polymers are highly viscous liquids, which limits the possibility of their practical application;

- the modified 1,2-polybutadiene obtained by this method due to the low molecular weight is characterized by a small complex of physico-mechanical properties; Due to their low strength, modified polymers can find only limited use.

An object of the present invention is a method for producing polymer products of the formula (1) containing dichlorocyclopropane groups in the main chain and in the side chains of macromolecules and different from the polymers described in the prototype:

- the composition of the polymer product - the total content in the polymer of the lateral 1,2-units (a) and 1,2-units modified with dichloropiclopropane groups (b) is at least 60 mol.%;

- a higher molecular weight (M _n ≥20000), which can be purposefully changed over a wide range of values depending on the requirements for the polymer product;

- a wider range of physicomechanical properties (modified polydienes are solid polymer products).

The specified technical problem is achieved by the fact that in the interaction of 1,2-polybutadiene with chloroform and an aqueous solution of an alkali metal in the presence of a quaternary ammonium salt as a phase transfer catalyst at a temperature of 40-50 ° C for 2-6 hours, as 1.2 -polybutadiene use atactic 1,2-polybutadiene with a number average molecular weight M _n from 20,000 to 70,000 and a content of 1,2- and 1,4-polymerization units in the macromolecules of 60-75 and 25-40 mol.%, respectively, and the synthesis is carried out at molar ratio of 1,2-polybutadiene: CHCl ₃ : Na OH: catalyst, 1: 4-14: 1.5-2: 0.001-0.002.

The inventive method allows to obtain polymer products of the formula (1) with a degree of functionalization (the content of dichlorocyclopropane groups) from 20 to 98% and the number average molecular weight M _n from 30,000 to 80,000.

When implementing the proposed method used industrial samples of 1,2-polybutadiene, in particular polymers produced by OJSC "Ephraim Plant SK". Samples of 1,2-polybutadiene were purified by reprecipitation in the chloroform – ethanol system, then the polymer was washed with alcohol and dried under vacuum at 60 ° C to constant weight.

Quaternary ammonium salts such as triethylbenzylammonium chloride (TEBAH) were used as a phase transfer catalyst; dimethylbenzyl (C ₁₀ -C ₁₈ -alkyl) ammonium chloride (catamine AB).

The invention is illustrated by the following examples.

Example 1. In a glass reactor equipped with a stirrer, reflux condenser and dropping funnel, 3.0 g (55.6 mmol) of 1,2-polybutadiene were charged, 16.6 g (222.4 mmol) of chloroform was added and stirred until dissolved . Atactic 1,2-polybutadiene with a number average molecular weight of M _n = 20,000 and a content of 1,2- and 1,4-polymerization units of 70 and 30 mol%, respectively, was used. To the resulting solution was added 0.024 g (0.11 mmol) of the TEBAH catalyst, heated to 50 ° C, and 8.9 g (111.2 mmol) of a 50% aqueous sodium hydroxide solution were dosed with vigorous stirring. The molar ratio of 1,2-PB: CHCl ₃ : NaOH: catalyst was 1: 4: 2: 0.002. The synthesis was carried out with vigorous stirring of the reaction mass at 50 ° C for 4 hours. Then the organic layer was separated and washed twice with water. The polymer from the organic phase was precipitated with alcohol and dried in vacuo at 60 ° C. The resulting polymer is a solid product with a chlorine content of 50.8 wt.%, Which corresponds to the degree of polymer functionalization of 98%, has a number average molecular weight of M _n = 30000, the content of units (a + b) is 70%.

The chlorine content in the polymer was determined by burning according to Sheniger (Klimova V.A. Basic micromethods for the analysis of organic compounds. M: Chemistry. 1975. - 208 p.).

The degree of functionalization of the polymer was calculated by the formula:

,

,

where: w (Cl) is the actual chlorine content in the polymer, wt.%; w _p (Cl) is the calculated amount of chlorine in the polymer at 100% functionalization of double bonds, wt.% (w _p (Cl) for dichlorocyclopropane derivatives of 1,2-PB is 51.8 wt.%).

The contents of units (a) and (c) in the starting 1,2-polybutadiene and units (b) and (d) in the modified polymer were determined by ¹³ C NMR spectroscopy. Quantitative ¹³ C NMR experiments were performed in the mode with broadband proton decoupling and delay between pulses 12 seconds. ¹³ C NMR spectra were recorded on a Broker AM-300 spectrometer with an operating frequency of 75.46 MHz, CDCl ₃ solvent, internal TMS standard. The assignment of signals (ppm) in the ¹³ C NMR spectrum of the modified polymer is given below:

¹³ C NMR spectrum (δ, ppm): 35.58 (t, C1); 40.26 (d, C2); 35.06 (t, C3); 45.70 (d, C4); 27.43-32.54 (t, C5, C8, cis + trans); 127.92-133.23 (d, C6, C7, cis + trans); 31.53 (t, C9, C12); 32.93 (d, C10, C11); 148.83 (d, C13); 115.36 (t, C14); 48.83 (d, C15); 27.56 (t, C16); 60.83 (s, C17); 65.90 (s, C18).

Examples 2-7. All operations were carried out in accordance with example 1. The experimental results are shown in table 1.

From the obtained results it follows that the use of atactic 1,2-polybutadiene with a number average molecular weight below 20,000 as the starting polymer does not make it possible to obtain modified 1,2-PB in the solid state of aggregation (Example 6). The use of an initial product with a molecular weight of more than 70,000 leads to a sharp decrease in the degree of functionalization of the resulting modified polymer (Example 5). The synthesis at a molar ratio of 1,2-PB: CHCl ₃ less than 1: 4 does not provide the necessary degree of functionalization of the obtained modified polymer (example 7). This circumstance is due to the fact that, at the indicated molar ratio, the amount of chloroform is insufficient to dissolve the starting polymer. An increase in the molar ratio of 1,2-PB: CHCl _{3 of} more than 1:14 leads to an excessive consumption of chloroform. The optimal is the molar ratio of 1,2-PB: NaOH equal to 1: 1.5-2. Reducing the consumption of sodium hydroxide less than the ratio of 1: 1.5, reduces the degree of functionalization of the resulting modified polymer. Moreover, the amount of sodium hydroxide is insufficient to generate the required amount of dichlorocarbene (according to equation 2). A molar ratio of 1.2-PB: catalyst equal to 1: 0.001-0.002, provides the process with sufficient speed. Thus, the synthesis is carried out at a molar ratio of 1,2-polybutadiene: CHCl ₃ : NaOH: a catalyst of 1: 4-14: 1.5-2: 0.001-0.002, which ensures the optimal process for the preparation of polymer products containing macromolecules dichlorocyclopropane groups.

The proposed method for producing polymer products of the formula (1) allows to synthesize modified polymers having, in comparison with the prototype:

- a different composition - the content of units (a + b) is 60-75 mol.%;

- significantly higher molecular weight M _n from 30,000 to 80,000 amu;

- representing solid polymer products.

The proposed method makes it possible to purposefully obtain polymer products (1) of a given composition, with a certain degree of functionalization and molecular weight, depending on the requirements for the polymer, and thereby produce polymer products with a higher complex of physicomechanical properties, which significantly expands the possibilities their practical application (allows you to use in areas where low molecular weight polymers cannot be applied). Obtained by the proposed method, modified polymers can be used independently as the basis for the production of various materials and products or used in various polymer compositions mixed with thermoplastics and elastomers.

Claims (2)

1. The method of producing polymers of the formula (1) containing dichlorocyclopropane groups in the main chain and side units of macromolecules

by reacting atactic 1,2-polybutadiene with chloroform and an aqueous alkali metal solution in the presence of a quaternary ammonium salt as a phase transfer catalyst at a temperature of 40-50 ° C for 2-6 hours, characterized in that the synthesis is carried out at a molar ratio of 1, 2-polybutadiene: CHCl ₃ : MaOH: catalyst equal to 1: 4-14: 1.5-2: 0.001-0.002. 2. The method according to claim 1, characterized in that atactic 1,2-polybutadiene with a number average molecular weight M _n from 20,000 to 70,000 and a content of 1,2- and 1,4-polymerization units in the macromolecules is used as the starting polymer 75 and 25-40 mol.%, Respectively.